The method and system for detecting operator alertness of an operator of a vehicle or machine comprises an image collection system. The graph is generated by determining the values of a successor state from the values of a predecessor state. The dielectric jacket has a substantially constant cross-sectional configuration along a length of the cable and comprises an inner layer formed from the first polymeric material and an outer layer formed from the second polymeric material. The isolation structure is formed such that the depth of the isolation structure is adjusted to a particular radiation source wavelength.